A seat belt is installed in a car in order to protect a vehicle occupant from the impact produced in a crash. And there are seat belts in which a gas generator for a pretensioner is installed as a means to protect a vehicle occupant in a crash of a car by tightening a seat belt. In addition, as an igniter of a gas generator for an air bag, an electric type igniter is known. As such prior arts, the followings are known.
In JP-A 2002-239371, a gas generator comprising a cup body 3 loaded with a gas generating agent, a igniter 5, and a holder 6 into which the cup body 3 and the igniter 5 are embedded and which contains the gas generating agent in the cup body 3 is disclosed. The cup body 3 and the holder 6 are connected by a reinforcing member 7 interposed in an exterior circumferential portion of the holder 6, and a flange portion 3a of the cup body 3 is fixed by crimping. Although in a portion of the reinforcing member 7 which contacts the flange portion 3a, a groove in a shape corresponding to the flange portion 3a is formed, production cost becomes high since forging and cutting is necessary in production of such a groove.
In JP-A 2002-172996, an igniter comprising a cup-shaped tube body 10, a transfer charge 15 contained in the tube body 10, a plug 7, a bridge wire 5 generating heat by electrification, and a fuse head 1 formed on the surface of the bridge wire 5 is disclosed. In the cup body 8, a stepped portion 9 is formed, a reinforcing member 26 and a flange 13 are engaged at this portion and crimped by a bent portion 30, and at the same time the stepped portion 9 is crimped ([0032]). Because of the existence of the bent portion and the stepped portion 9, the cup body 8 has an enlarged outside diameter at those portions. In combustion of a gas generating agent P, big pressure is generated in the cup body 8, and at this time, it is possible that the stepped portion 9 deforms radially outwardly by the pressure, connecting strength of the crimping portion decreases and parts scatters.
In JP-A 2001-106017, a gas generator comprising a charging tube body 1 charging a gas generating agent, a storing tube body 2 storing an ignition agent, and a holder 3 sealing the gas generating agent P and the ignition agent 6 is disclosed. The charging tube body 1 and the holder 3 are sealed by crimping of a crimping ring body 4. However, since the ring body 4 is pressed into the holder 3 axially, it is possible that, in the combustion of the gas generating agent P, the ring body 4 falls by the pressure generated inside the loading tube body 1. In addition, a connection by arranging a screw on an interior circumferential surface of the ring body 4 and an exterior circumferential surface of the holder 3, a method of coupling the ring body 4 to the holder 3 by a bolt et al., and so on are disclosed. But, these methods bring increase in the number of parts and processing cost.